I was having fun this morning with the new acoustic mapping tool I made. It includes a custom Teensy 3.1 breakout board that holds four mic pre amps, and connects to a 144 segment led strip. The strip is separated in the code into four regions, and the microphones are physically placed at the center of each of these regions on the strip.
I'm still playing around with the display and calibration routine a bit, and I'm going back and forth on whether or not to tag each segment with a unique color, so you can distinguish between microphones more easily.
Here's a quick video of what it looks like in action. In the beginning of the clip, there's a single blue led animation that increments along the strip while the teensy calibrates. The teensy listens for the maximum and minimum ranges of SPL amplitude and then uses this information to set the ranges on the display. Once that's set, the rest of the lights come on.
And this is what is looks like when you take a picture!
Here's another at 123Hz.
Looking at the two pictures it's easy to see that 123Hz is more resonant along this one path in my living room. There are also less extreme phase cancellations at this frequency along this path than at 280Hz (i.e less dips in the volume as you move around).